org.mule.runtime.api.streaming

Interface CursorProvider<T extends Cursor>

All Known Subinterfaces:

CursorIteratorProvider, CursorStreamProvider

All Known Implementing Classes:

AbstractCursorStreamProvider, InMemoryCursorStreamProvider

@NoImplement
public interface CursorProvider<T extends Cursor>

Provides instances of Cursor which allows concurrent access to a wrapped stream.

The provider maintains all the allocated resources necessary to power all the open cursors.

When this provider is closed, it will not open any new cursors and invokations to openCursor() will fail. However, the allocated resources will not be released until all open cursors are closed. The runtime will be in charge of doing that, no intervention is required from the client.

Since:

1.0

See Also:

CursorStream

Method Summary

Modifier and Type	Method and Description
void	close() Closes the provider in the sense that it will not yield any more cursors.
boolean	isClosed()
T	openCursor() Creates a new Cursor of type T positioned on the very beginning of the wrapped stream.
void	releaseResources() Releases all the resources currently held by this provider.

Method Detail

openCursor

T openCursor()

Creates a new Cursor of type T positioned on the very beginning of the wrapped stream.

Notices that this method enables concurrent random access by providing the ability to open several cursors. However, each cursor should not be used concurrently since Cursor does not guarantee thread safeness.

It is the invokers responsibility to make sure that the returned cursor gets closed, since otherwise whatever resources held by the underlying buffer will never be released.

Returns:

a new CursorStream

Throws:

IllegalStateException - if invoked after the close() method has been invoked

close

void close()

Closes the provider in the sense that it will not yield any more cursors. However, all active cursors will remain functional. When the last of them is closed, then any resources associated to this provider will be released.

releaseResources

void releaseResources()

Releases all the resources currently held by this provider. Any open cursors generated by this provider will cease to function, which means that this method should only be invoked once the close() has already been invoked (to prevent new cursors from being opened) and all the current ones have already been released.

This method should ONLY be invoked by the runtime

isClosed

boolean isClosed()

Returns:

Whether the close() method has been invoked on this instance or not